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Is NUMA that rare? Back in 2007-2008 or so, my company bought some rack servers fitted with 48-core AMD Opteron (Magny-Cours), which weren't particularly expens
by lobster_johnson 9y ago
Is NUMA that rare? Back in 2007-2008 or so, my company bought some rack servers fitted with 48-core AMD Opteron (Magny-Cours), which weren't particularly expensive, and had a NUMA architecture.
We didn't have HPC workloads, just Postgres, which uses one OS process per connection, and performance was terrible as a result.
- anarazel 9y ago> We didn't have HPC workloads, just Postgres, which uses one OS process per connection, and performance was terrible as a result. I'd bet, but not too much, that that was more due to a) postgres' internal locking implementation scaling horribly at that time b) zone_reclaim_mode leading to bad behaviour around IO.
- lobster_johnson 9y agoIt's possible, but we weren't testing 48 clients at that time, just our normal workload, which had much less parallelism than that. The person in charge of setting up the systems explained the performance issues as being due to NUMA.
- velox_io 9y agoYou may find this a fascinating read. It's regarding how SQL Server has it's own threading scheduler to bypass the Windows scheduler. When ran on a machine with HyperThreading enabled it will only use 50% of the CPU, I guess they're going after CPU Cache utilisation. It's really hard to find a decent article on the subject, here's two of the best I've found. https://www.mssqltips.com/sqlservertip/4403/understanding-sql-server-schedulers-workers-and-tasks/ https://www.mssqltips.com/sqlservertip/4403/understanding-sq... https://docs.microsoft.com/en-us/sql/relational-databases/thread-and-task-architecture-guide https://docs.microsoft.com/en-us/sql/relational-databases/th...